R闪亮错误:未找到模式“函数”的对象“plotFunction”

I want to create a function for that holds the downloadHandler function and feeds it its details dynamically but I keep getting the message

我想为它创建一个包含downloadHandler函数的函数并动态地向它提供它的细节，但是我一直在获取消息

"object 'plotFunction' of mode 'function' was not found"

未找到模式'function'的对象'plotFunction'

My function for downloading is as follows:

我的下载功能如下:

downloadPlots <- function(fileName,plotFunction,fileFormat,fileContentType){
if(fileFormat=="pdf"){ #because it doesn't require specification of contentType. Others do
  downloadHandler(
    filename = fileName,
    content = function(file) {          
      pdf(file, pointsize = 12, bg = "white", res = NA)
      FUN <- match.fun(plotFunction) 
      FUN()
      dev.off()
    }
  )
}else{
  downloadHandler(
    filename = fileName,
    content = function(file) {
      if(fileFormat=="png")
        png(file, pointsize = 12, bg = "white", res = NA)
      FUN <- match.fun(plotFunction,descend = TRUE) 
      FUN()
      dev.off()
    },
    contentType = fileContentType
  )
}

}

}

This is how the function is called

这就是函数的调用方式。

output$histPng <- downloadPlots("histogram.png",histogram(),"png","image/png")

In the ui.R, the code for downloading the plot is as follows:

在ui中。R，下载该地块的代码如下:

downloadButton('histPng','PNG')

1 个解决方案

#1

I think the problem (without any testing) may be that you are passing your plot function to downloadPlots() incorrectly. Remove the parentheses from histogram in your function call:

我认为问题(没有任何测试)可能是您不正确地将情节函数传递给downloadplot()。从函数调用的直方图中删除圆括号:

output$histPng <- downloadPlots("histogram.png",histogram,"png","image/png")